Railway car retarder



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INVENTOR r A O. Granda/u am# Hlt ATTORNEY l.. O. GRONDAHL RAILWAY CAR RETARDER Jan. 17, 1933.

Original Filed Sept. 11. 1930 CEI Patented Jan. 17, 1933 UNITED STATES PATENT OFFICE LARS O. GRONDAHL, F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA RAILWAY CAR RETARDER Application led September 11, 1930, Serial No. 481,163.

My invention relates to railway car retarders, and has for an objectthe provision of novel and improved retarders of the electrou magnetic type.

" showing a modified form of retarder embodying my invention. Fig. 4 is a horizontal sectional View of the retarder shown in Fig. 3. Fig. is a vertical transverse sectional view showing another modified form 7"- of retarder also embodying my invention.

Fig. 6 is a horizontal plan view of the retarder shown in Fig. 5.

Similar reference characters refer to similar parte in each of the views.

Referring first to Figs. 1 and 2, the reference characters 1 and 1a designate the two rails of a railway track. These rails are connected by a magnetizable bar 2 carrying an energizing winding 9. The bar 2 is attached to the underside of each rail by cleats 4 and bolts 5, and extending in each direction from the bar 2 along the under side of each rail is a member 3 which is also of magnetizable material. A railway car traveling along the 51 track mils 1 and lat is represented by WhGlS 6 and 6a and an aXle 7 It will be obvious that when a car is present, the path of the magnetic flux created by current in winding 9 will be through the bar 2, track rail 1, wheel 6, aXle 7, wheel 6a and rail 1a to the bar 2. As the car travels past the retarder, eddy currents will be produced in the wheels and in the rails. The members 3 have low magnetic reluctance compared to the track rails, so that the greater part of the flux will follow these members until it reaches a point approximately under the car wheels, as illustrated by the flux lines 8 in Fig. 2. It will be seen, therefore, that as the wheels pass the retarder, the magnetic flux Renewed December 3, 1932.

will follow the wheels, and that the flux in the wheels constitutes a rotating field in the material of which the wheels are made. The result will be eddy current losses produced in the'members3, the track rails, and the ca r wheels, the energy for which'losses is absorbed from the moving car.

These eddy current losses are highly effective in producing braking action, and the action is extremely uniform, because t-he magnetic circuit contains no variable air gaps.

Referring now to Figs. 3 and 4, the retarder is substantially the same asthat shown in Figs. 1 and 2, but the structural details are somewhat different. In Figs. 3 and 4 the bar, which is here designated 2a, is provided with members 10 and 10a, which extend along the inner sides of the webs of rails 1 and 1a, respectively, and the outer sides of the webs of these railsare provided with similar members 11 `and 11a, respectively. The members 10 and 11 are attached to rail 1 by bolts 12, and the members 10n and 11L are attached to rail 11 by similar bolts, these bolts, of course, extending through the webs of the rails. The bar 2n, the members 10 and 10a and the members 11 and 11a are all made of magnetizable material. The operation of the retard er shown in Figs. 3 and 4 is the same as that of the retarder shown in Figs. 1 and 2.

Referring now to Figs. 5 and 6, the retarder, in the form here shown, comprises two special rail sections X and Xa connected by a bar 2b, all of which parts are made of material having lower permeability and lower specific resistance than ordinary track rails. The bar 2b is integral with the special rail section Xa, but the special rail section X is detachable from the bar 2b in order to enable the winding 9 to be applied to the bar. As here shown, the bar 2b is attached to the special rail section X by bolts 13. The advantage of the retarder shown in Figs. 5 and 6 is that it eliminates some of the air gaps that might prove troublesome under actual operating conditions.

In connection with all three forms of retarders embodying my invention, it is understood that when a car is to be retarded,

the winding 9 is energized as the car approaehes the retarder and remains energized until the car has left the retarder, or until the desired retardation has been attained. The control of the winding 9 forms no part of my present invention, and, consequently, the controlling circuits are omitted from the drawing.

Although I have herein shown only three 10 forms of oar retarders embodying my invention, it is understood that various changes and modifications may be made therein within the scope or" the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A railway car retarder comprising a magnetizable member extending along the v inner side of the web of each track rail, a magnetizable bar connecting an intermediate point in one of said members with an intermediate point in the other, and an energizing Winding on said bar.

2. A railway car retarder comprising a magnetizable member extending along each side of the web of each track rail, a magnetizable bar connecting an intermediate point of the member on the inner side of one rail with an intermediate point on the member on the inner side of the other rail, and an energizing winding on said bar.

3. A railway car retarder comprising two magnetizable members extending along and gin Contact with the two track rails respectively, a magnetizable bar connecting an intermediate point in one of said members with an f intermediate point in the other, and an energizing winding on said bar.

In testimony whereof I affix my signature.

LABS 0. GRONDAI-IL. 

